Between lessons about the Revolutionary War and the functions of Congress, juniors in several history and U.S. government classes at Palmer High School in Colorado Springs are taught to defend themselves against disinformation.

The students, many of them on the cusp of voting age, spend up to two weeks each fall exploring how falsehoods, prejudices and opinions can lurk in the many places they get information. They learn to trace the origins of documents, to validate a website by leaving it to consult other sources and to train a critical eye on the claims made by TikTok influencers and on YouTube videos.

“With students and adults alike, it’s just easy to look at stuff on social media and take it as it is and not question it,” said Paul Blakesley, who has taught students about media and information literacy for several years at the high school. “It can be difficult to push through that apathy, but it’s well worth trying.”

Children and teenagers are not the only ones susceptible to misinformation: Several studies suggest that older adults are more likely to struggle to recognize fake news and are the most likely to share it.

But with young people spending more time online, where misleading and false narratives swirl around the upcoming midterm elections, the Covid-19 pandemic and other topics, educators are increasingly trying to offer protection. Using techniques updated for the digital age, they are teaching students that virality does not confer legitimacy, that content can be fabricated or manipulated and that a .org domain does not make a website trustworthy.

At Palmer High School, Mr. Blakesley tries to demonstrate how to distinguish between good information and bad: Who are the sources? What is their perspective? When is it appropriate to turn to Wikipedia?

Alarmed by the surge of misinformation online, several educational groups representing more than 350,000 teachers in math, social studies and other disciplines created an alliance to better support those trying to teach media literacy. One of the founding groups, the National Association for Media Literacy Education, said its own membership had more than doubled in the past five years.

Federal and state legislators have tried in recent years to support media literacy in public schools. Five states, including Colorado, passed language since early 2020 that required education departments to take steps such as providing literacy resources and revising learning standards, according to the nonprofit group Media Literacy Now. Many of the existing laws amount to legislative endorsements of the need for literacy education rather than actual mandates. Only one state, Illinois, requires that high school students be taught how to gain access to and analyze media messages.

Without an explicit mandate from lawmakers, though, some schools — many of which face staff shortages and political fights over classroom subjects — struggle to integrate media literacy into their curriculum. And those that manage to do so often teach it using outdated checklists delivered in short bursts, rather than as an integrated part of core subjects.

But media and information literacy advocates said the difficulties were outweighed by the dangers if young students fail to recognize rhetorical red flags and fall prey to confirmation bias online, where they could unwittingly feed rumors and contribute to polarization.

“There are challenges with getting this into schools,” said Jimmeka Anderson, who founded the youth-focused group I AM not the MEdia. “But it’s a necessity for the way we live today because we’re all engaging in this online space, especially youth.”

For a study published last year, researchers at Stanford University asked 3,446 high school students to evaluate several types of content. They did not do well. In one example, a website claimed to offer facts about climate science, but was actually tied to the fossil fuel industry. It duped nearly 97 percent of the students.

Such findings suggest that many students need help learning to filter the barrage of information coming their way, said Sam Wineburg, one of the researchers, who leads the Stanford History Education Group. He and other researchers have suggested teaching students to read laterally, fact-checking online information by exploring beyond the original website.

Other studies have presented websites promoting the preservation of imaginary animals, which the vast majority of children and adolescents surveyed did not recognize as hoaxes. One global study this summer found that nearly half of young adults shared misinformation because they thought it was true, while a third did so impulsively. Many said they were too busy to verify the information or felt pressure to weigh in on a current event, according to the research, which was led by the Poynter Institute for Media Studies.

Gracie Gilligan conducted her own study this year in Maynard, a small liberal town in Massachusetts. Ms. Gilligan, a recent Maynard High School graduate, found that 47 percent of students in her school district rarely talked to their parents and guardians about what made media sources trustworthy. Only 52 percent of seniors had been taught that media companies make money by selling audience attention.

However, in what she considered a heartening sign, 95 percent of seniors said they had done a research project that required them to gather information from multiple sources and summarize their findings.

Ms. Gilligan, who worked on the survey with the nonprofit group Media Literacy Now and the Media Education Lab at the University of Rhode Island, realized that Instagram was becoming one of her primary information sources, via infographics and “posts that contained one-sentence explanations of really complex issues.”

“A lot of my friends and my peers got really polarized at a very young age, and people were really angry at anyone who believed differently than them,” she said. “And a lot of that came from having a very one-sided view of the issues that we were seeing.”

This year, Ms. Gilligan turned 18 and has planned to vote for the first time in the midterms. But many instructors believe that media literacy education should start much earlier, in middle or even elementary school, when children are just beginning to venture online.

Efforts to appeal to younger students have included illustrated books and search engine scavenger hunts. The National Association for Media Literacy Education used a video game theme for its “Level Up” conference in July, which featured graphics modeled after the Super Mario video game franchise and a session about harnessing the power of memes. Google created an online game, Interland, in which a robot explores digital worlds such as a “Reality River” that “flows with fact and fiction.”

Since 2004, Timothy Krueger has taught history to younger teenagers in the North Syracuse district in upstate New York. His students once raised a bogus TikTok conspiracy theory that Helen Keller faked her blindness and deafness. Others had said they were unvaccinated against Covid-19 because their parents had told them, inaccurately, that the shot would make them infertile.

Mr. Krueger began including more lessons about evaluating evidence and fact-checking. In November, a pilot program he helped design with the American Federation of Teachers will be piloted in Cleveland, helping in part to train educators to teach media and information literacy using “safe” methods to shield them from harassment.

“We’re under attack — it’s now such an openly polarized society, where teachers are afraid to talk about hot topics or controversial issues,” Mr. Krueger said.

But, he added, teachers are “Step 1” in showing young people how to think clearly for themselves: “If we want them to be a truly intelligent constituency, we have to start now.”

New educational efforts are constantly being deployed. Twitter and Google have so-called pre-bunking initiatives to warn users about common misinformation tactics. The nonprofit News Literacy Project, which said the number of students using its free Checkology curriculum surged 248 percent between 2018 and 2022, recently introduced a short elections misinformation guide on Flip, a video-based online platform for teachers.

But Peter Adams, a former teacher who heads research and design for the News Literacy Project, is pushing for a broader consensus on the types of skills students should learn and the results educators want. Without it, he worries that lessons could backfire.

“Some methods have become entrenched in schools that almost imply that students should question everything they see with an equal amount of skepticism,” he said. “This can invite young people to conclude that all sources of information are equally suspect or, even worse, to inflame a kind of nihilism, that all sources of information have some sort of hidden motive or are out to manipulate them in some way.”